Motorcycle construction



Sept. 14, 1943. w. L. cARLsoN MOTORCYCLE CONSTRUCTION Filed Jan. 23, 1942 attorney,

Patented Sept, 14, 1943 I await I The present invention relates generxallly to rnoter-cycle construction and'more'particularly to the looa'tiolra-nd construction of a-n air filter for "theinetorcycleengine. j In present practice it' is customary to provide filters-for the air isupplyflto I carbhretors of vehicle 4 engines butfth provis'iong'oi *an -airffilter one =niotor cycleenginemresents certain problems {which-are noteneou'ntered in-automotive practice wherei;n 'the 'air filter together with other engine "accessories may be convenientlylocated within 'theengine compartment} --Itis highlyjdesirahle'fifor"instance;thatthe-alr filter be so constructed and" located as "to "be "protected against physical ,jdamage and the env trance of -an g-excessive amount of road' dust, dirt and moisture. In motorcycles particularly fadaiitedf'for military use,"it"has alsoibeenf-fonnd c lesirable to locate the filter 'at a relativelyfhigh elevationftoinsure the'proper function ng ther li i 1 when the motorcycle is operated across creeks io'r b 'r l ivelidee -x s a i fiitistherefore the principal object of the PIGS-1 'ent irrventionfto sp construct and 'position ir. f l r enamewr l that hei t r w lf d warm-vi r'rcteqiedf sa n t hysi al damage and the entranceoi an excessive amount o'f road dust nal section through the filter and adjacent parts 1 of the motorcycle frame. I l

Referring first to Figure 1, the motorcycle as a whole has been'shown diagrammatically as including the frame 4, wheels 6, handle bars ,8, saddle l0, and the power plant-indicated generally at I2. The power plant mayinclude any known type of engine but has been diagrammatically illustrated as a two cylinder opposed engine with the longitudinal axis of the cylinders arranged transversely of the frame 4. Only a single cylinder head l4 andcarburetor l6 appear in the drawin but it will be understood thatsuch parts are duplicated on the opposite side of the motorcycle from that shown in Figure 1. It will also be rro r'o tcycrn co fin men- Itcheszor through accumulations :of' water'wh-ich 4 dersteed-that the powerplant} will include the 'al "controls and accessories "andf-willf be pru- 'vid'e'd with'anyfsuitableitransrriission and'dri've -to "'therearjwheel: i

he mo orcycle frame is shown as generally *mvertedjU '-shaped in 'crossgsectionwithfa substantially horizontal wall 18 and substantially "vertical "depending walls [23] which are *spacedto receive and form aho-using for-'partsof thedrlvc and 1, power plant accessories with thleframe ender.

o'the franre and the'saddle post 24', the wall 1' 3 Thy pwardlyextending fiangefifi tortciverh removable air-filter unit indicated generally 28. An enclosediaif space -31} is-provided-witlim he ,20 frame '4 beneath the-openingin wall td-which s constituted by portions of the frame walls-and sheet metal partitionswithin thei-wallfs such as fshown at??? and 734; ,Adjacent'the' lower portion e air space 3!! ea'c'h of the frame side walls llll ovide d vvith an fopenin'g' defined by the out- I y exterrding'fiangeifi. These-openings are substantially "in horizontal alinernent with "the on *each' side :of" the frame and areshown as connected hereto corrduits or elbows -38 which "are preferablyformedhfrubberorsimflarflexible f'fira'te'ri'al to permit slight relative -Aroveineiitbtween the engine and motorcycle frame such as mightoccurt by reason of vibration or a resilient 5 mounting of the engine on the frame.

The air filter unit 28 may assume various forms but is shown vas including any suitable filtering medium 40 such as copper mesh or gauze which is confined between screens 42 within a casing 40 formed by the lower cup-shaped member 44 and upper member 46 which may be secured together as by crimping'the edge'of one member around the edge of the other member'in the manner shown in Figure 3. The casing members 44 and '45 46 may also be secured together by a central hollow sleeve 48 which is adapted to receive the securing post 50. As indicated in Figure 3, the casing member 46 and the lower wall of the casin member 44 are provided with openings through 50 which airmay pass through suchmembers and the filter medium andscreens into the air space 30; g r

It will be apparent that the air filter unit 28 constitutes a self-contained unit which may be pre-assembled and readily removed and replaced ended rearwardly to form the rear "wheel 1 *Dire tyibe ahrn wntp imidri w s: -f between't front eridcdnnectionZ-Z thereof 15 irame"4is provided-viithanopening deflned respective air intake p a-s sag ej sof "the carburetors v whenever desired. The filter unit is adapted to.

be secured against the flange 26 of frame wall l8 by means of the wing nut 52 which is screwthreaded on the upper end of the post 50 with a cover 54 interposed between the nut 52 and the flanged upper end of the filter sleeve 48. This cover 54 is bent upwardly in spaced relation to the upper'member 46 of the, filter' casing and formed with a depending peripheral flange 56 to provide a downwardly opening air inlet slot.

unit 28 under the saddle l0 and the mounting,

physical damage.

level to reduce the entrance of road dust, dirt and},

moisture to a minimum.

Although shown and described in connection with a motorcycle of the two-wheeled type it will .be understood that th e filter. location and mount: ing relative to theframe-may beemployed within J the scope of the present invention in motor Qtricycle or three-wheeled motorcycle construction.

- It will also be understood that I. contemplate all such changes and modifications in the specific construction shown herein as may come .within vthe scope-ofthe appended claims i e V 1. In a motorcycle, aframe, a saddle ons'aid rectlyunder said saddle with portions' of said saddle extending over said opn'inggand means to supply air to said carburetor includinga'closed passage extending from said opening to said carburetor.

2.-'Ihe elements set forth in claiml inwhich within said. frame open- 4 3. In a-motorcycle,a frame; 'a saddle on said ,frame, an engine, a carburetor for said engine,

said frame including walls. defining a, hollow space under said saddle and provided with. openin gs therein, an air filter in one of said. openings, and 'aconduit; extending from another of said openings to saidcarbureton- I 4. In a motorcycle, a frame incl'udi'ng .asubistantially horizontal wall, a saddle above said' ,horizontal wall, an engine, a carburetorgfor said engine, said horizontalwall being .provided with I an opening under said 'sadle, and means to supply air to said carburetor including a closed passage extending from said opening to said carburetor.

5. In a motorcycle, a frame, an engine, a carburetor for said engine,said frame including a wall provided with an opening therein, an'air filter detachably secured to said frame'within said opening, and means defining a closed passage exv H tending from said opening to said carburetor. It will be seen that the location of the filter l 6. In a motorcycle, a frame, an engine, a carburetor for said engine, said frame including a substantially horizontal Wall and depending spaced vertical *Walls and partitions forming herewith a; hollow air space within'said frame,

said horizontal wall being provided with an air inlet opening and one of said vertical walls being i v i 4 H H H 3 0 frame, an engine, a carburetor for said engine," .-gsaid frame being provided with an opening -di-' provided with an air outlet opening, and a conduit extending from said air outlet opening to said'carburetor; l p v 3; 7. In a motor cycle, aframe, a saddle on said f-r ame; an engine, a pair of carburetorsfor said engine, said frame being provided withan open- 8. In a motorcycle, a longitudinally extending frame, an engine, a pair of carburetors-for said ,engine, said carburetors being located ;at opposite sides of said frame, said frame including walls defining a hollow space within said frame,

one of said walls being provided with an ,air inlet opening, an airiilter insaid opening, and conduits atopp'ositesides of said frame extending from said space to said carburetors.

9. In a motorcyclefa longitudinally extending v frame an engine, a pair of carburetors'for said ,engine, saidcarburetors being located at opposite sides of saidframe, said frame'including a substantially horizontal wall and-depending spaced vertical walls and partitions forming therewith vided with air outlet'openirigsand conduits on opposite sides of saidframe extending from said 50 outlet openings to said carburetors. 

